High mileage F150 and still loving it!

Love my 98' F150 SC 4X4. Just hit 190,000 miles still runs great. Have done most of the maintenance myself replacing brakes etc. (Upgraded to "Hawk" Super Duty Pads) what a difference!!! and Classic tube braided SS brake lines. It's never left me stranded and is the most dependable vehicle I've ever owned. Love this era truck. Still looks like new. It's also the best riding vehicle I've purchased. When it's not working, we love to go for drives in it and have pulled several trucks out with ease. What a great feeling it is to own a FORD!

Ok, I know you said "have", but I wanted to put in my two cents anyway. I just traded in my 1998 F150 Ext Cab 4x4 4.6 with 180000 and going strong. I owned it for 9 years and 110000 miles....and they weren't all easy. I had large tires, k&n cold air kit, hypertech tuner, and dual exhausts for pretty much the entire time I owned the truck and it was a beast. I haul firewood and haul a little livestock from time to time so I definately used it hard and it always got the job done. (I'm surprised I never broke any leaf springs) I didn't ever have to do anything to the truck in terms of major maintenance. Pretty much the only thing was routine maintenance and any aftermarket stuff I was putting on. I have no complaints and wish I could have kept it, but with 2 kids, the 3 door extended cab was getting crowded. Ended up with a crew cab super duty, but that was definately one tough truck.

fwmud, your discription is that of a motor with a lot of carbon in the heads and on piston crowns causing pre-ignition.
It's from such sources as oil past the intake valve guides, oil past the rings and poor grades of gas.
You might benifit at this point from a water treatment out of a spray bottle introduced before the mass air meter to remove some of the carbon while the motor is running.
Then add Seafom into the intake for a while.
Let motor set for about 10 minutes and restart.
If it is going to help, you will see a lot of smoke out the tail pipe until it clears.
Then you may repeat the treatment.
If there is oil getting into the cylinders from any source, then you will have to repeat as needed by listening to a tendency for spark knock again on 87 fuel.
Let us know if it works out for you.
Changing plug heat range is of no help because it's not the source of the issue.
What happens is the carbon stays in a very hot 'glowing' state and ignites the air/fuel mix sleightly ahead of normal ignition.
This in effect makes the ignition 'not' in full control of the event.
The glowing carbon acts as if the igntion timing were too far advanced, on a random basis.
The spark knock is the sudden rise in cylinder pressure peaking to quickly after top dead center with the piston to close to top dead center such that the pressure cannot act on a ROD/PISTON/Crank that is too near in a 'straight alighnment'.
With little place to go it rings the head, piston, rod, crank and cylinder walls you hear a knock.
The fact that higher octance reduced the effect is proof the fuel slows down combustion which is what higher octane does. Otherwise is has no other magic qualities.
You might also check to see if the knock sensor is working and there is no code set for it being od.
If it is working it should pull back the ignition timing and normally cause a loss of power as soon as you hear it.
However if carbon is doing the dirty work, the knock sensor will have less effect because it can't control pre ignition from a hot spots in the cylinders no matter how much it tries to retard the timing. In fact it could make it worse.
Another item to look at is the EGR for leaking exhaust gas back into the intake. this will advance the ignition timing, and cut fuel causing a tendency to ping as well for different reasons.
I know this is a lot to swallow but read it again and think about it.
All you can do is try these treatments and checks and observe the results.
Then you have an idea what's going on.
Good luck.

WOW! And thanks so much. I've used seafoam in the fuel and vacum system. I'll try the other this weekend.
Overall the truck has been fantastic. Not nearly my first Ford and certainly not my last.
Thanks again Bluegrass for the "mouthfull" .

Take the filter housing apart and spray ahead of the air meter.
Use enough to make the engine stumble but keep it running with hand throttleing. Let the mortor recover and do it repeatedly.
The water will cool the air meter bridge which makes the PCM think there is more air than there is coming in, but that's not a problem.
Just use a more or less fine spray and not a lot of 'whole water' same as very humid air intake.
The water turns to steam vapor in the cylinder and takes a lot of carbon loose.
When this happens the motor stumbles because the plugs can't fire very much until the situation clears out.
Good luck..

I have a '97 Expedition with 210,000 on it. It has by far been the best ruck I have ever had. Last summer I pulled a Caddy on a car trailer up to Canada and back (about 1500 miles) without a problem with over 200,000 miles on the truck. The total weight of the whole rig was over 14,000 pounds; not bad I say!

I have a 2000 f150 5.4 4x4 supercrew 6.5bed Lariat with 229,000. I just purchased a few months ago from the sole owner.

Strong running truck, with alot of rust LOL (Michigan). I think rust would have eaten truck before any engine problems. Have welded new support beam under bed, patched holes in bed, replaced driver rear shackel, passenger front pads. (new POWERSTOP rotors and pads on their way)

Hi group. I'm new here and was doing some reading when I saw this post & had to add my 02 cents. I've got a 2000 F150 4X4 sport with if you can believe it 339343 km on the 5.4 triton and it still runs great. Picked it up for 2500 dollars a year ago for yard and house renos and haven't really spent a dime on it since I got it. Its got some quirks and the tranny has lost it's overdrive but overall, this is a super truck. i'll put it up on my hoist in the spring and do some front end work and replace a seal in the differential but I can't say enough about how happy I am overall with this truck. It's my second F150 and I'm hoping with some TLC and regular fluid changes, I'm going to see If I can coax 500000 km out of it. The tranny will have to be done, but hey..I think it will be money well spent if I can get a used one for a good price...

This is a terrific site and I hope to learn alot from the knowledgeable people that visit here.

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